Ascariasis--Ascaris InfectionURL: http://www.cdc.gov/ncidod/dpd/parasites/ascaris/factsht_ascaris.htmSource: Centers for Disease Control and Prevention, National Center for Infectious Diseases, Division of Parasitic Diseases"An ascarid is a worm that lives in the small intestine... Ascarid eggs are found in the soil. Infection occurs when a person accidentally ingests (swallows) infective ascarid eggs..."

More than a billion people worldwide are infected with one or more species of intestinal nematodes. The ascariasis is one of the roundworm parasites more common seen of human being and it is calculated that the world population's fourth part is infected. Although that the clinical pictures of this illness courses mostly with silent form or chronic symptomatology, the massive infestation in children can give place to serious complications that require surgical urgency attention for experts.

Every year, 60.000 deaths are attributed directly to this infection. This helmintic infection is acquired by the ingestion of eggs; the larvae during their migration go by the lung to complete their maturation, they ascend for the respiratory tree and then continuing go up for later to be swallowed and arrive to the small intestine where they become adults. http://www.ispub.com/ostia/index.php?xmlFilePath=journals/ijs/vol8n2/ascaris.xml

Migrating larvae may transmit other organisms, causing bacterial pneumonia. Rare cases of airway obstruction have also been reported. Other much less common presentations include lacrimal drainage obstruction, acute interstitial nephritis, and encephalopathy.

Intestinal nematode infections affect one fourth to one third of the world's population. Of these, the intestinal roundworm Ascaris lumbricoides is the most common. While the vast majority of these cases are asymptomatic, infected persons may present with pulmonary or gastrointestinal complaints. Ascariasis predominates in areas of poor sanitation and is associated with malnutrition, iron-deficiency anemia, and impairments of growth and cognition.

Once ingested, eggs hatch, releasing small larvae that penetrate the intestinal wall. Larvae migrate to the pulmonary bed via the portal veins, during which time they may cause pulmonary symptoms (eg, cough, wheezing). After migrating up the respiratory tract and being swallowed, they mature, copulate, and lay eggs in the intestines. Adult worms may live in the gut for 6-24 months, where they can cause partial or complete bowel obstruction in large numbers, or they can migrate into the appendix, hepatobiliary system, or pancreatic ducts.

In the United States, approximately 4 million people are believed to be infected.

The rate of complications secondary to ascariasis ranges from 11-67%, with intestinal and biliary tract obstruction representing the most common serious sequelae. Although infection with A lumbricoides is rarely fatal, it is responsible for an estimated 8,000-100,000 deaths annually, mainly in childrenhttp://www.emedicine.com/emerg/topic840.htm